History of Firewalls By Colby Shifflett Dr Grossman

History of Firewalls By: Colby Shifflett Dr. Grossman Computer Science 420 12/01/2009

The Need for Firewalls � Before the use of firewalls, networks were extremely vulnerable to intrusions and data leaking. ◦ Extremely weak security ◦ No virus security � The first firewall was introduced in 1985 by the IOS software division - Cisco � The first published papers on firewalls was not until 3 years after its first deployment by Digital Equipment Company

What is a firewall? �A firewall is a system or set of systems that are used to control access ◦ Designed to block all unauthorized communication and accept all authorized. � According to Cheswick and Bellovin, AT&T Bell Labs firewall engineers, a firewall should be used as a network chokepoint. (Late 1980’s)

First Generation Firewalls � First Generation Firewalls are also known as packet filtering firewalls � Packet filtering routers were key in making the first firewalls � Very simple filtering device ◦ Have a set of rules for the firewall �Ip, port, or protocol based ◦ Based on set of rules, accept or reject communication request �Uses packet header

First Generation Firewalls continued… � Network packet filtering offered more security than ever before for networks � Was very straight forward to understand, implement, and manage ◦ Greatly helped popularity in commerce business � Evolved extremely quickly after first working model demonstrated its capabilities

Second Generation Firewalls � Second Generation Firewalls are also known as Circuit Level Firewalls � Validates connections prior to allowing data exchange � After validation, a session is open and only data from source is permitted access ◦ Every exchange of information is validated and monitored �Source/Destination Ip or port, time of day, user, password, or protocol are validation methods � No data is accepted unless a session is open

Third Generation of Firewalls � Third Generation Firewalls are also known as Application Layer Firewalls or Proxy Firewalls � Operate at the 7 th or Application layer of the OSI model ◦ Monitors the protocol that is being used � Have the ability to run as a piece of software or a standalone device ◦ Software firewalls are still very commonly used today �Mc. Afee �Norton � DEC’s first release was named SEAL and grew quickly in popularity

Fourth Generation Firewalls � Fourth Generation Firewalls are also known as stateful firewalls � Most important upgrade from First Generation Firewalls is the ability to keep track of the TCP connection state ◦ Greatly prevents hackers access ◦ Firewalls are able to determine if packets are a part of a new connection or existing connection � Relies on a three way handshake with TCP

Any Questions? Thanks for listening!